Definition/Description

Cervical myelopathy is the result of spinal cord compression in the cervical spine. Any space occupying lesion within the cervical spine with the potential to compress the spinal cord can result in this degenerative disease.[1][2] Cervical myelopathy is predominantly due to pressure on the anterior spinal cord with ischaemia as a result of deformation of the cord by anterior herniated discs, spondylitic spurs or an ossified posterior longitudinal ligament.[3] Human histological studies have revealed degeneration of the anterior horns, cavity formation, and demyelination in the severely compressed spinal cord. The spontaneous course of myelopathy is characterized either by long periods of stable disability followed by episodes of deterioration or a linear progressive course. The presentation of a cervical myelopathy varies in accordance to the severity of the spinal cord compression as well as its location.[4]

Clinically Relevant Anatomy

There are seven cervical vertebrae and eight cervical nerve roots.[2][5] The spinal cord is the extension of the central nervous system outside the cranium. It is encased by the vertebral column and begins at the foramen magnum.[6] The spinal cord is an extremely vital part of the central nervous system, and even a small injury can lead to severe disability.[7]

A complex system of ligaments serves to stabilize and protect the cervical spine. For example, ligamentum flavum extends from the anterior surface of the cephalic vertebra to the posterior surface of the caudal vertebra and connects to the ventral aspect of the facet joint capsules. A ligament that is often involved in this condition is the posterior longitudinal ligament. It is situated within the vertebral canal, originating from the body of the axis, where it is continuous with the membrana tectoria, and extends along the posterior surfaces of the bodies of the vertebrae until inserting into the sacrum.[7]

Chronic cervical degeneration is the most common cause of progressive spinal cord and nerve root compression. Spondylotic changes can result in stenosis of the spinal canal, lateral recess, and foramina. Spinal canal stenosis can lead to myelopathy, whereas the latter two can lead to radiculopathy.

Cervical spine myelopathy resulting from sagittal narrowing of the spinal canal and compression of the spinal cord is present in 90% of individuals by the seventh decade of life.[8]

Epidemiology /Etiology

Cervical spondylotic myelopathy is the most common disorder of the spinal cord in persons older than 55 years of age.[5][9][10] Radiologic spondylotic changes increase with patient age - 90% of asymptomatic persons older than 70 years have some form of degenerative change in the cervical spine. Both sexes are affected equally. Cervical spondylosis usually starts earlier in men (50 years) than in women (60 years). It causes hospitalization at a rate of 4.04 per 100,000 person-years.[5][11]

The causes of cervical myelopathy can be divided into different categories:

Static factors: A narrowing of the spinal canal size can result from disc degeneration, spondylosis, stenosis, osteophyte formation at the level of facet joints, segmental ossification of the posterior longitudinal ligament and yellow ligament hypertrophy, calcification or ossification. Patients with a congenitally narrow spinal canal (<13mm) have a higher risk for the development of symptomatic cervical myelopathy.[4][11][12]

Dynamic factors: Due to mechanical abnormalities of the cervical spine or instability.[4]

Mechanism of Injury / Pathological Process

The onset is insidious and gradual, which is related to degenerative changes in the cervical spine anatomy. Osteophytic overgrowth, thickening of the ligamentum flavum (dorsally) and of the posterior longitudinal ligament can compress the spinal cord. The intervertebral discs dry out resulting in loss of disc height, which increases compression of the vertebral end plates and osteophytic spurs develop at the margins of the end plates. The degenerative changes encroach on the spinal cord and cause compression.

stiffening of connective tissues, such as the ligamentum flavum at the dorsal aspect of the spinal canal, which can impinge on the cord by "buckling" when the spine is extended

degeneration of the intervertebral discs together with subsequent bony changes

other connective tissue changes

Cord compression is thought to be a combination of static compression and intermittent dynamic compression from cervical motion (flexion/extension).

Clinical Presentation

Cervical spondylotic myelopathy can cause a variety of signs and symptoms. Symptoms are divided into two groups: long-tract and segmental symptoms. Onset is insidious, typically in persons aged 50-60 years.

Early symptoms of this condition are ‘numb, clumsy, painful hands’ and disturbance of fine motor skills.[4] Weakness and numbness occur in a non-specific/non-dermatomal pattern. As spinal cord degeneration progresses, lower motor neuron findings in the upper extremities, such as loss of strength, atrophy of the interosseous muscles and difficulty in fine finger movements, may present. Additional clinical findings may include: neck pain and stiffness (decreased ROM, especially extension), shoulder and scapular pain, paresthesia in one or both arms or hands, signs of radiculopathy, Babinski and Hoffman's sign, ataxia and dexterity loss.[5][13][14] Typical neurological signs of long-tract involvement are exaggerated tendon reflexes (patellar and achilles), presence of pathological reflexes (e.g. clonus, Babinski and Hoffman's sign), spastic quadriplegia, sensory loss and bladder-bowel disturbance.[12]Once the disorder is diagnosed, complete remission to normality never occurs and spontaneous temporary remission is uncommon. In 75% of the patients, episodic worsening with neurological deterioration occurs, 20% have slow steady progression, and 5% experience rapid onset and progression.[4]

Common Symptoms

Distal weakness

Decreased ROM in the cervical spine, especially extension.

Clumsy or weak hands

Pain in shoulder or arms

Unsteady or clumsy gait

Increased reflexes in the lower extremities and in the upper extremities below the level of the lesion.

Diagnostic Procedures

A detailed and thorough neurological examination is the current standard to diagnose the presence of cervical myelopathy. A magnetic resonance image (MRI) is considered the best imaging method for confirming the presence of cervical stenosis, cord compression, or myelomalacia, elements germane to cervical spine myelopathy.

Clinical Examination

The diagnosis of CSM is primarily based on the clinical signs found on physical examination and is supported by imaging findings of cervical spondylosis with cord compression.[9] According to Cook et al,[15] selected combinations of the following clinical findings are effective in ruling out and ruling in cervical spine myelopathy. Combinations of three of five or four of five of these tests enable post-test probability of the condition to 94–99%:

gait deviation

+ve Hoffmann’s test

inverted supinator sign

+ve Babinski test

age 45 years or older

Other clinical examination tests often used for myelopathy include:[5][9]

Although these tests exhibit moderate to substantial reliability among skilled clinicians, they demonstrate low sensitivity and are not appropriate for ruling out myelopathy. One method used to improve the diagnostic accuracy of clinical testing is combining tests into clusters. These often overcome the inherent weakness of stand alone tests.[5][15]

Imaging

Plain radiographs alone are of little use as an initial diagnostic procedure. MRI of the cervical spine can identify spinal canal stenosis, as well as rule out spinal cord tumors.

An MRI is most useful because it expresses the amount of compression placed on the spinal cord and demonstrates relatively high levels of sensitivity and specificity. [5][13] Anterior-posterior width reduction, cross-sectional evidence of cord compression, obliteration of the subarachnoid space and signal intensity changes to the cord found on MR imaging are considered the most appropriate parameters for confirmation of a spinal cord compression myelopathy. [5] More than half of patients with cervical spine myelopathy show intramedullary high signal intensity on T2-weighted imaging, mainly in the spinal gray matter. [16] Radiographic cervical spinal cord compression and hyperintense T2 intraparenchymal signal abnormalities (MRI) correlate well with the presence of myelopathic findings on physical examination[17].

Management / Interventions

There is no consensus about the treatment of mild and moderate forms of cervical myelopathy. Surgical treatment has no better results than conservative treatment over two years of follow-up. [20]. Patients with cervical myelopathy that are treated with a conservative approach (anti-inflammatory medication and physical therapy) may have some short term benefit in relief of painful symptoms. Because the condition is degenerative and progressive, slow and continued progressive neurologic deterioration will occur.

Medical Management

People who have progressive neurologic changes (such as weakness, numbness or falling) with signs of severe spinal cord compression or spinal cord swelling are candidates for surgery. Patients with severe or disabling pain may also be helped with surgery.[22] When myelopathy is caused by factors of a progressive nature, such as spinal cord tumors, surgical treatment is likewise indicated. [23][24].

People who experience better surgical outcomes often have these characteristics:• The symptom of an electrical sensation that runs down the back and into the limbs• Younger age• Shorter duration of symptoms• Single rather than multiple areas of involvement• Larger areas available for the cord

The principal aim of surgery for cervical myelopathy is decompression of the spinal cord. The surgical techniques include multilevel discectomies or corpectomies with or without instrumented fusion, laminectomy with or without instrumented fusion or laminoplasty. [4] Surgical decompression is generally considered if the symptoms affect daily life but early surgical intervention is thought to be more effective. Therefore, early detection may be the key to minimize postoperative sequelae. [16]

Final outcomes from the surgery vary. Typically, one-third of patients improve, one-third stay the same, and one-third continue to worsen over time, with respect to their pre-surgical symptoms. [10][22]

Cervical traction and manipulation of the thoracic spine: useful for the reduction of pain scores and level of disability in patients with mild cervical myelopathy. Other signs and symptoms, such as weakness, headache, dizziness, and hypoesthesia, are positively affected. [25]Clinical Treatment Tool-kitClinical Treatment Tool-kit

Cervical stabilization exercises: when there is anteroposterior instability of the vertebral bodies of a degenerative nature, vertebral segment stabilization of the cervical spine can be performed with a pressure biofeedback unit (PBU), performing 10 repetitions sustained for 10s, beginning with 22mmHg with the intention to progress to 30mmHg. [22]

Dynamic upper and lower limb exercises (flexion and extension) with the use of the PBU on the neck.[22]

Proprioceptive neuromuscular facilitation: for the upper and lower limbs.[22]

In surgical cases, the physiotherapist still has an important role, both before and after the surgery. In the pre-operative phase, the physiotherapist needs to become thoroughly familiar with the patient's history and about his/her activities of daily living that they are aiming to return to. The physiotherapist will inform the patient about the treatment program and the expectations after the surgery. There are different tests to develop a thorough picture of the patient's baseline pre-operative status such as walking tolerance, Neck Pain and Disability Scale, Neck Disability Index and lung function.

Exercises to improve mobility and proprioception will be given to the patient. The patient starts unencumbered stabilisation exercises and then progresses to more active mobilisation exercises. During the day the patient is encouraged to perform ADLs. On the second day, the intensity of the exercises is increased and are then progressed to include standing and walking exercises. Assuming typical progress with rehabilitation, the patient can go home after the ninth day. At home, physiotherapy continues with active exercises. The physiotherapist has to make sure that the patient can continue his/her ADLs and increases the intensity of it daily. After a straightforward rehabilitation, there are no limitations to the ADLs for the patient. Also important in the rehabilitation is to improve the posture[28]. The main goal is to make the patient able to participate in society again without permanent restrictions due to the surgery.

Case Studies

Clinical Bottom Line

Cervical myelopathy is the result of spinal cord compression in the cervical spine and is the most common disorder of the spinal cord in persons older than 55 years of age. Cervical compression in myelopathy is predominantly due to pressure on the anterior spinal cord with ischaemia and to deformation of the cord by anterior herniated discs, spondylitic spurs or an ossified posterior longitudinal ligament. Early symptoms of this condition are ‘numb, clumsy, painful hands’ and disturbance of fine motor skill. The diagnosis of CSM is primarily based on the clinical signs found on physical examination and is supported by imaging findings of cervical spondylosis with cord compression. Once the disorder is diagnosed, complete remission to normality never occurs, and spontaneous remission to normal normality is uncommon. Exercises and techniques that may help relieve symptoms of cervical myelopathy include: cervical traction, manual therapy techniques, proprioceptive neuromuscular facilitation, cervical stabilization exercises and dynamic upper and lower limb exercises.

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